Urban slums in Lagos, Nigeria, face significant water scarcity due to inadequate infrastructure and management of rainfall. A mixed-method approach combining surveys (n=500) and focus group discussions (n=20). Rainwater harvesting was adopted by 36% of surveyed households, with higher adoption rates in areas with more frequent rainfall. The study highlights the need for targeted community engagement and policy interventions to maximise water conservation benefits. Develop tailored rainwater harvesting solutions and implement education programmes targeting vulnerable communities.